Can I see my Sketch results?
Sketch results are available only to the hiring organization; they are not released to applicants.
Is there any class or manual to help me score better on the Sketch?
The Sketch examines characteristics acquired through life, education, and work. There is no course or reference material to explain the Sketch or assist you in “scoring better”.
Can I take the Sketch again?
Generally no. However, if it has been a while (a year or more) and you are not applying to a posting that is using a version of the Sketch that you have already taken, you will be offered the opportunity to take the Sketch again.
Trying to repeat the Sketch in order to "practice" is disallowed, as is copying the Sketch in any form, which will immediately disqualify you from any employer that uses the Sketch.
If you have a VERY good reason for needing to take the Sketch again, this can be arranged through the hiring organization.